The present invention is directed generally to the monitoring of a patient's vital signs, particularly during open-heart surgery.
Open-heart surgery requires precise intensive monitoring of the patient's condition throughout the operation and during the recovery period. Pulmonary and radial arterial pressures are among the many parameters constantly monitored during open-heart surgery. These pressures, along with many other parameters, are important to the anesthesiologist. One of these other parameters is the rate-pressure product. The rate-pressure product is indirectly related to the myocardial oxygen supply and can be obtained from the product of the systolic pressure and the heart rate.
Present monitoring systems include a transducer and amplifier connected to a catheter implanted in the patient's radial artery. The transducer amplifier and EKG amplifier is connected to a CRT (cathode ray tube) screen which displays the wave forms of the heart rate and systolic pressure. The anesthesiologist reads the wave forms and calculates the rate-pressure product. In addition to being time consuming, this procedure is prone to error, because of the poor resolution of the CRT screen and because of the possibility of matching the heart rate with the wrong blood pressure wave form when calculating the rate-pressure product. These and other difficulties have been obviated by the present invention.
It is, therefore, an outstanding object of the invention to provide a vital signs monitor which provides automatic digital display of vital sign parameters.
Another object of the invention is the provision of a vital signs monitor which automatically calculates and displays the rate-pressure product from the systolic pressure and heart rate.
A further object of the present invention is the provision of a vital signs monitor that is capable of averaging the rate-pressure product for a plurality of heart beats and is capable of being selectively programmed to display the average rate-pressure product for a selected number of heart beats.
It is another object of the instant invention to provide a vital signs monitor that has an alarm and is selectively programmable for a high rate-pressure value and a low rate-pressure value, in such a way that the alarm is activated when either the low or the high value is displayed.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.